1. Field
The present disclosure relates to a wireless communication system, more particularly, to a method, an apparatus, software, or a recoding medium that stores software, which transmits or receives uplink control information through a Physical Uplink Control Channel (PUCCH) in a wireless communication system.
Furthermore, the present disclosure relates to a wireless communication system, more particularly, to a method, an apparatus, software, or a recoding medium that stores software, which simultaneously transmits or receives uplink acknowledgement information and periodic channel state information (CSI) in a wireless communication system.
2. Discussion of the Background
Hybrid automatic repeat request (HARQ)-acknowledgement information, that is, HARQ-ACK information, which indicates whether a receiving end successfully decodes data transmitted from a transmitting end in a wireless communication system, may be transmitted or fed back from the receiving end to the transmitting end. For example, an error detection code (e.g., a cyclic redundancy check (CRC)) may be added based on a codeword unit, to downlink data that is transmitted from a base station to a terminal. Accordingly, the terminal may generate acknowledgement (ACK)/negative acknowledgment (NACK) information based on a codeword unit, and may transmit the same to the base station through an uplink channel. Similar to the transmission of uplink ACK information which responds to the downlink data transmission, an ACK with respect to uplink data that is transmitted from the terminal to the base station may be transmitted from the base station to the terminal through a downlink channel.
A rank indicator (RI), a precoding matrix index (PMI), channel quality information (CQI), or the like are defined as information that a receiving end feeds back to a transmitting end in a wireless communication system to which a multi-input multi-output (MIMO) technology is applied. The feedback information is generally referred to as channel state information (CSI). For example, a terminal may feed back a preferred RI and/or PMI to a base station, based on a measurement result associated with a downlink channel from the base station. Here, the RI preferred by the terminal may correspond to a downlink transmission rank value that may have the highest transmission rate when it is used by the base station in a given channel state. Also, the PMI preferred by the terminal is an index indicating a precoding matrix appropriate for a channel state measured by the terminal, in a codebook which is the set of precoding matrix candidates. The codebook may be determined in advance and shared by the base station and the terminal. Also, the CQI is calculated based on the RI and/or PMI reported by the terminal, and may correspond to a modulation and coding scheme (MCS) level that is applied to downlink transmission. That is, the CQI may indicate an MCS level that provides an acceptable packet error rate when a predetermined rank value and pre-coder information is applied. A point in time when to report a CSI of the terminal and the range of frequency (or frequency resolution) to be measured may be controlled by the base station. In association with the point in time when to report, a periodic CSI report and aperiodic CSI report may be supported. Generally, the periodic CSI report may be performed through a physical uplink control channel (PUCCH), and the aperiodic CSI report may be performed through a physical uplink shared channel (PUSCH).
In a general wireless communication system (e.g., a system according to 3GPP LTE release 8 or 9), a single frequency band is used. However, in an advanced wireless communication system (e.g., 3GPP LTE release 10, 11, or 12), carrier aggregation (CA) is used to bind a plurality of frequency bands so that effects are provided as if a frequency band having a logically large bandwidth is used. For example, two contiguous or non-contiguous bands (that is, two different component carriers (CC) having different carrier frequencies) in the frequency domain may be aggregated, and a higher transmission rate may be supported. In CA, a cell may be formed of a downlink resource (that is, downlink component carrier (DL CC)) and/or an uplink resource (that is, uplink component carrier (UL CC)). Here, the UL CC is not essential, and a single cell may correspond to only the DL CC, or may correspond to both the DL CC and the UL CC. The DL CC and the UL CC may be expressed as a carrier frequency, and the carrier frequency may indicate a center frequency in a corresponding cell. The cell may be classified as a primary cell (PCell) that operates in a primary frequency and a secondary cell (SCell) that operates in a secondary frequency. The PCell and the SCell may be generally referred to as a serving cell. The PCell indicates a serving cell that provides a security input and Non-Access Stratum (NAS) mobility information in the state of radio resource control establishment or re-establishment. The set of serving cells may be configured by adding one or more SCells to a PCell based on the capability of a terminal. That is, the set of serving cells configured for a single terminal may include only a single PCell or may include a single PCell and one or more SCells.
The conventional CA defines that a maximum of 5 CCs are aggregated. However, recently, the CA technology enhancement that aggregates more than 5 CCs (e.g., a maximum or 32 CCs) has been discussing. To support the enhanced CA (eCA), the introduction of a new PUCCH format that has a larger capacity than the existing PUCCH format has been discussing.
Also, in the conventional CA, uplink control information (UCI) (here, the UCI generally indicates a HARQ-ACK, CSI, a scheduling request (SR), and the like) through a PUCCH is transmitted only in a primary cell (PCell), which is a limitation. However, in the eCA, supporting a PUCCH transmission in a secondary cell (SCell), is also discussed.
Therefore, when a new PUCCH format is configured, there is a desire for a detailed scheme for simultaneously transmitting HARQ-ACK information and one or a plurality of periodic CSIs. Also, there is a need for a detailed scheme for supporting the transmission of uplink control information when a new PUCCH format is set for a UE.